Block signaling system for railways.



A. V. T. DAY.

BLOCK SIGNALING SYSTEM FOR RAILWAYS.

APPLICATION FILED JUNE 15.1908.

2 SHEETS-SHEET 1.'

By. I

Patented Dec. 19,1916.

A V. T. DAY.

BLOCK SIGNALING SYSTEM FOR RAILWAYS.

APPLICATION FILED JUNE 15. 1908.

1,208,752, Patented Dec. 19,1916.

2 SHEETS-SHEET 2.

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ALBERT v. T. DAY, on NEW ROCHELLE, NEW YORK, ASSIGNOR, BY MESNE ASSIGN-MENTS, To HALL SWITCH & SIGNAL COMPANY, OF NEW YORK, N. Y., A consona-TION 0F MAINE.

BLOCK SIGNALING SYSTEM FOR RAILWAYS.

Specification of Letters Patent.

Patented Dec. 19, 1916.

To all whom it may concern.

Be it known that I, ALBERT V. T. DAY, a citizen of the United States,residing at New Rochelle, in the county of WVestchester and State of NewYork, have invented a certain new and useful Improvement in BlockSignaling Systems for Railways, of which the following is aspecification, reference be ing had therein tothe accompanying drawings,forming part thereof.

My invention relates to electric block signaling systems for railwaysand particularly to' normal danger systems for electric ra1lways.

Still more particularly, my invention relates to that class of electricblock signaling systems wherein each signaling block controls one ormore track relays located at a distance fromthe home signalof thatblock, but controlling such home signal through a line circuit.

It is one object of my invention to utilize the said line circuit ofeach block to control the distant signal as well as the home signal atthe rear end of that block, and also to control on the normal dangerplan the home and distant signals at the advance end of that block andthe home signal at the advance end of the next block ahead. In itsaccomplishment of this object and in its general nature, my presentinvention is an improvement on the invention disclosed in my applicationfiled June 15, 1908, Serial No. 438593, wherein I have broadly claimedcertain broad features also embodied in the systems herein disclosed,but not claimed herein.

Other objects and features of the invention will be apparent from thefollowing description of the illustrated embodiment of the invention. 7g

I will now describe the embodiment of my invention illustrated in theaccompanying drawings, and will thereafter point out the invention inclaims. 7 V

Figure 1 of the drawings is a diagram of a signal system embodying thepresent invention and operating with normally open line circuits. Fig. 2is a diagram of a similar system operating with normally closed linecircuits;

The drawings represent two successive blocks and portions of theadjacent blocks. The signal apparatus of one track of a double-tracksystem is illustrated, the other track and its signal apparatus beingomitted as they are in all respects similar. The three signal stationsshown are designated respectively as B, C and D. For convenience, thenext station in the rear of B, which is not shown, will be hereinafterreferred to as station A, and the next station in advance of D will behereinafter referred to as station E. As the apparatus at the severalstations is precisely alike, similar reference numbers are used inconnection with similar parts of the apparatus at the several stations,but in the following description the numbers are followed, wherenecessary, by letters to indicate at which station the part referred tois located.

The signal system of the drawings is of the type in which the trackrails are continuously conductive and are provided with cross-bonds oflow impedance at the ends of v the blocks, so that the rails may beused, if

desired, as conductors for traction current. The track circuits by whichthe automatic operation of the signals is primarily'controlled areformed by the rails 1 and the cross-bonds 2, and are energized bytransformers 3 located approximately at the center of each block. Thesecondary windings of the transformers are connected across the rails,so that each track circuit has two branches, the current flowing fromone terminal of the transformer, in opposite directions, through onerail, to the ends of the block, through the cross-bonds to the otherrail, and back to the other terminal of the transformer. Thetransformers are constantly energized with alternating current throughtransmission wires 22 connected with a generator 23.

The track circuits control the signal apparatus through the operation ofinductive track coils 6 and 7 at the ends of each block. These coils arelocated at the ends of the track circuits adjacent to the cross-bondsand are disposed between, and close to, short portions of the rails, andare inductively energized by the currents in the track circuits. Thecoils 6 and 7 at each station are connected, respectively, with trackrelays 4: and 5.

The track relays are of the alternatin current polarized type. Eachrelay has a field magnet constantly energized with an alternatingcurrent, and a pivoted arn'iature provided with a coil connected withone of the track coils. The armatures actuate c011- tac t fingers bywhich the line circuits are controlled. Referring to station C in Fig. 1of the drawings, the field magnets of the relays are energized throughfeed wires 10 and 11 connected with the secondary ter' minals of atransformer 12 energized by the transmission wires 22. Relay 4 has anarmature 13 of which the coil is connected with track coil 6. Thearmature carries a contact finger 14 cooperating with a front contact 15and a back contact 16. Relay 5 has a similar contact finger 8Ocooperating with front and back contacts. The relays at the otherstations are similar to those at C. As the armatures are normallyenergized by the track coils, the contact fingers are normally heldraised against the front contacts.

At each station there is a home signal 17 and a distant signal 18. Thesesignals have a bias to danger position, but are provided withelectrically-controlled mechanism for moving them to clear position.This apparatus is not shown, as it may be of any ordinary or suitableform. It is normally deenergized, so that the signals stand normally atdanger position.

The selective operation of the signals, by which either the home signalalone, or both the home signal and the distant signal at a station, maybe'clcared, is effected by a polarized line relay 8 controlling thelocal sig nal circuits. This relay is of the same type as the trackrelays, and has a field magnet constantly energized from the samesource. Its armature coil is interposed in the line circuit extending tothe signal station next in advance and its contact finger, whichnormally occupies a neutral position, moves to right or left accordingto the phase or instantaneous direction of the current in its armaturerelative to current in its field, so that a reversal in the phase orinstantaneous direction of the current in the line circuit moves thecontact finger from right to left or vice versa.

A second line relay 9, of the non-polarized type, is interposed in eachline circuit at the advance end of the block over which the line circuitextends. This relay has two armatures and contact fingers 19 and 20, andthese are so arranged that they require currents of different strengthto actuate them. Contact finger 20 requires current of maximum or fullstrength, and in the drawings this is indicated diagrammatically by aspring 21 connected with the contact finger. Contact finger 19 isactuated by a current of lesser or medium strength. Under certainconditions a still weaker current of minimum strength flows through therelay coil without actuating either contact finger. The reversal ofphase of the current in the line circuit, to control the polarized linereas shown in Fig. 1, the line circuits are held open by line relays 9and the signals stand at danger position.

With the apparatus in normal position, suppose a train moving in thedirection of the arrow enters the block BC. The wheels and axles of thetrain short-circuit the right-hand branch of the track circuit, andtrack coil 7B is deenergized. Contact finger 30 of line relay 5B fallsand engages its back contact, and the line circuit between B and C isthereby closed. This circuit is energized by current from transformer 12at station C, through feed wires 10C and 11C, and is as follows: fromfeed wire 10C through wire 26 to contact finger 25 of the pole-changingswitch, through the contact finger and its upper fixed contact to wire27C and line wire 28, through the line wire to station B, through wire29B to the back contact of the track relay 5, through contact finger 30,back through line wire 31 to station C, through front contact 15 andcontact finger 1 1 of track relay 4C, through wire 32 to the magnet ofline relay 9C, thence through wire 33 to the upper contact of contactfinger 24 of the pole-changing switch, and through the contact finger24: to feed wire 11.

As the current in the circuit above de scribed passes through thewinding of only the single relay 9C, it is current of full strength andoperates both contact fingers of relay 9C. This operation of relay 9Cresults in closing a line circuit from C to D, and it is this linecircuit which acts to clear the home signal at D and both signals at C.The current is derived from transformer 12D and the circuit is asfollows: from feed wire 10D through wire 26, contact finger 25 of thepole-changing switch and its upper contact, wire 27, line Wire 28, andwire 29C, through the armature coil of line relav 8C, through wire 10 tothe contact fingers of line relay 9C, through contact finger 20 and itsfixed contact to wire at, through front contact and contact finger 30 ofrelay 5, back through line wire 31 to station D, through front contactand contact finger 14 of track relay 4CD, through wire 32 to the magnetof line relay 9D, thence through wire 33 to contact finger 2-4 of thepole-changing switch, and thence to feed wire 11.

One immediate effect of the circuit just described is to cause linerelay, 8G to move its contact finger to the right and close the localcircuit through the home signal. This circuit is energized, through feedwires 10 and 11C, by transformer 12C and is as follows: from feed wire10 through wire 26 and common Wire 38 to home signal 17 through wire 36to the right-hand contact and contact finger 35 and thence through wire39 to feed wire 11. A second immediate effect of the closing of the linecircuit between C and D is to operate line relay 9D. In this connectionit is to be noted that since the current in this line circuit traversesthe windings of both relay 8C and relay 9D, it is reduced by theresistance of the two windings to current of second strength and onlycontact finger 19 of relay 9D is actuated.

The secondary effect ofthe closing of the line circuitbetween C and D isthe closing, through the operation of contact finger 19D, of the linecircuit between D and E. This circuit is similar to the circuit abovedescribed between C and D, with the exception that it passes throughcontact finger 19 of relay 9D and through a resistance coil 4:1, andnot, as at C, through contact finger 20. It passes through line relay 8Dand operates the relay to move its contact finger to the right and clearhome signal 171). The home signals are now clear at both C and D, andthe distant signal at C is next cleared through the action of the homesignal at D. This signal, in clearing, reverses the polechanging switchat D and thereby reverses the current in the line circuit between C andD. Line relay 8C thereupon moves its contact finger from right to leftand closes both local signal circuits, the return from distant signal186 being through wire 37 and one of the left-hand contacts of therelay, while the return from the home signal is the same as beforeexcept that it traverses one of the two left-hand contacts instead ofthe single right-hand contact.

The function of the resistance coil 41 above referred to is to preventthe successive operation of the line relays 9 from proceeding beyondstation D. The line circuit be tween D andE is closed, as abovedescribed, to operate relay 8D, and it therefore energizes relay 9E. Thecurrent, however, is of third strength only, since it traverses not onlythe windings of relay 8D and relay 9E, but also resistance coil 41D.Consequently the'current, although it suffices to operate relay SD,which is sensitive to current of third strengtlnis not suflicient tooperate either contact finger of relay 9E, and the apparatus at Eremains in normal position. By the use of currents of three strengths inthe manner above described, the relays 9 operate, therefore, insuch'manner that the relay at the advance end of the block occupied by atrain is energized with current of full strength energized with currentof third strength,

and does not close the line circuit in advance, and thereby the advanceoperation of the apparatus 18 l1m1ted to two line circuits and thecorresponding relays 8 by which the sig- 7 nals must be cleared at theend of the block occupied by the train and at the end of the next blockin advance.

With the signals cleared as above de scribed, the train proceeds throughblock BC. As the train nears the advance end of the block, the easternbranch of the track circuit becomes operative again and track coil 7Band track relay 5B are again energized. This does not affect thesignals, however, for while the line circuit through the contact fingerof relay 5B is broken by the return of the relay to normal position, asubstitute local circuit has previously been established by the actionof the train in short-circuiting the western branch of the track circuitand deenergizing track coil 6C and track relay 4C. This circuit isestablished by the engagement of contact finger 14 of relay 4G with itsback contact and is as follows: from feed wire 10C through wire 26,contact finger 25 of the pole-changing switch and its lower contact (theswitch having been reversed by the clearing of home signal 17C), throughwire 33 to the magnet of relay 9C, through wire 32 to the back contactand contact finger of relay 4C, and thence through contact finger 24Land its lower contact, to feed wire 11. Relay 9C thereby remainsenergized as before, the reversal of the current having no efiect on itas it is non-polarized.

As soon as the train leaves block BC and enters block CD, the operationsabove described are advanced one block, and the home signal at E andboth signals at D are cleared, while track relay 4C is again energizedand block B-C returns to normal condition.

WVhile the first train is still in CD, suppose a second train approachesB from A.

Owing to the presence of the first train, one

of the track relays 5C or 4D is denergized, so that line relay 8C is cutout of the line circuit between C and D. Since this relay isinoperative, the home signal at C is not cleared. The second trainoperates to close the line circuit between B and C, as in the case ofthe first train, but as the home signal at C is not cleared, thepole-changing switch at O is not moved from normal position, and linerelay 8B therefore merely moves its contact finger to the right. therebyclearing the home signal at B, but leaving the distant signal at danger.If the second train runs into block B C while the first train is stillin C-D, neither signal at C will clear,

owing to line relay 8C being cut out as above described.

By a slight change in the connections the system may be arranged tooperate with normally closed line circuits, as shown in Fig. 2. Here theapparatus is the same as in Fig. 1, except that no back contacts areused on the track relays, and the contact finger 20 of the non-polarizedrelay cooperates with a bank contact 43 instead of av front contact.Currents of two strengths are used in the line circuit, the normalcurrent of full strength acting to attract both armatures of the linerelays 9, while current of half strength acts to attract only thearmatures and contact fingers 19.

In the normal condition of the apparatus current from transformer 12Cflows through line circuit BC and energize relays 8B and 9C. Thecircuit, starting at feed wire 11C, passes through wire 26, contactfinger 25 and its upper contact, wire 9.7,line wire 28, wire 29B, thearmature coil of relay 8B, contact finger 19 of relay 9B, which isnormally held against its fixed contact, wire lat, the fixed contact andcontact finger of track relay 5B, back to station C through line wire31, through the fixed contact and contact finger of track relay 4C,through wire 32 to the winding of relay 9C, thence through wire 33 tothe upper contact of contact finger 24-, and back to feed wire 10. Thiscurrent is of full strength and both armatures of relay 9C are attachedso that contact finger 19 is in closed-circuit position and contactfinger 20 is in open-circuit position. Since line relay SB is alsoenergized, its contact finger stands normally in righthand position. Thelocal circuit through home signal 17B is not closed, however, for itpasses through contact finger 20 of relay 9 and is thus normally heldopen. The same condition of the apparatus exists in all the otherblocks, each line relay 9 being energized by current from the homestation and each line relay 8 being energized by current from the nextstation in advance. Suppose now that a train enters block B-C andshort-circuits one branch of the track circuit. Either track relay 5B ortrack relay 4G is now deenergized and its contact finger falls andbreaks the line circuit between B and C. By this action line relay 8B isdeenergized, without immediate efiect, and line relay 9C is deenergizedwith the efiect of clearing home signal 170. This occurs through theaction of contact finger 20, which engages its back contact when soreleased and closes the local signal circuit. This circuit passes fromteed wire 10, through wire 4L2, the contact finger and the back contact,thence to contact finger 35 of line relay 8, through the right-handcontact and wire 36 to the signal, and back by common wire 38 and wire26 to feed wire 11.

Current from transformer 12 thereupon clears the signal. Thedeenergization of relay 9C has a further action owing to the release ofcontact finger 19. This contact finger' forms normally, as abovedescribed, part of the line circuit between C and D. VJhen the contactfinger is released from its fixed contact, the line circuit has tofollowan alternative path through resistance coil 41, and the current isreduced to half strength. This reduction in current afiects line relay9D, acting to release contact finger 20D and close the local signalcircuit at D. The home signal at D is thereupon cleared in the samemanner as the home signal at C.

The clearing of the home signal at D acts to clear the distant signal atC, for the polechanging switch at D is reversed, thereby reversing thecurrent in line relay' 8C, and the contact finger 35 of this relaythereupon moves from right to left and sends clearing current throughboth wires 36 and 37 to the respective signals. The clearing of the homesignal at G acts to reverse the corresponding pole-changing switch, butthis has no efiect since the line circuit between B and C is alreadyopen. The automatic action proceeds no farther than station D, so longas the train is in block B-G, for contact finger 19 of line relay 9]) isnot released by the reduction in strength of the current in line circuitCD, and therefore line circuit DE is not affected.

When the train leaves block BC and enters block (1-D, the actions abovedescribed are advanced through a block, the home signal at E and thedistant signal at D being cleared.

If a second train approaches B from A while the first train is still inblock C-D,

line relay 9B is deenergized and closes the local circuit to clear thehome signal at B. The current in line circuit BC is also reduced to halfstrength so as to release contact finger 20 of line relay 9G. The homesignal at C is not thereby cleared, however, for the local circuit at Gis open owing to the de'elnergization of line relay 8G consequent uponthe presence of the train in block CD and the action of track relays 5Cand dD. The pole-changing switch at trated in the accompanying drawings,,Within the nature of the invention and the scope of the followingclaims.

I claim:

1. A block signal system comprising successive signaling blocks, linecircuits extending through the various blocks one for each block, andmeans for producing current in the line circuits, and at the rear end ofeach block a signaling apparatus including means for effecting a. changeof current strength in the line circuit extending in one direction andmeans for effecting a change of current direction in the line circuitextending in the opposite direction, and each signaling apparatus alsoincluding translating means in control of the signal indication and re-V sponsive to a change of current direction in the line circuitextending in said one direction and also including translating means incontrol of the signal indication and responsive to a change in currentstrength in the line circuit extending in said opposite direction.

A block signal system comprising signal controlling conductors extendingalong the railway, means for producing current in the conductors sinalino' aaoaratuses at successive points along the railway includingmeans at various of said points for effecting a change of currentstrength in the signal controlling conductors extending in one directionand also for effecting a change of current polarity in the signalcontrolling conductors extending in the opposite direc tion, and eachsignaling apparatus being responsive to a change of current polarity ofthe controlling conductors extending in said one direction andresponsive to a change in current strength in the controlling conductorsextending in said opposite direction.

A block signal system comprising signal controlling conductors extendingalong the railway, means for producing current in the conductors,signaling apparatuses at successive points along the railway includ ingmeans at various of said points for effooting a change of currentstrength in the signal controlling conductors extending in advancedirection and also for effecting a change of current polarity in thesignal controlling conductors extending in rearward direction, and eachsignaling apparatus being responsive to a change of current polarity inthe controlling conductors extending in advance direction and responsiveto a change in current strength in the controlling conductors extendingin rearward direction.

In testimony whereof I have afiixed my signature in presence of twowitnesses.

ALBERT v. T. DAY. Witnesses HENRY D. WILLIAMs, BERNARD CownN.

Copies of this patent may be obtained for five cents each, by addressingthe "Commissioner of Patents, Washington, D. 0.

